A fabrication method of fabricating a structure capable of being used for generation or detection of electromagnetic radiation includes a forming step of forming a layer containing a compound semiconductor on a substrate at a substrate temperature below about 300.degree. C., a first
A metal ion emission device for emitting a metal ion by applying voltage to a molten liquid metal includes a needle-like part having an internal opening in which the liquid metal can be moved. The needle-like part has a first opening for supplying the liquid metal to the opening and a
